Soil Substrate or Dirted Tank - A How to Guide

[gmartins]

Re: Introduction to Underwater Gardening with Soil Substrate

.... and there is evidence that for some aquatic species, some nutrients such as K, uptake is done mostly via water-column.

Barko JW (1982) Influence of potassium source (sediment vs. open water) and sediment composition on the growth and nutrition of a submersed freshwater macrophyte (Hydrilla verticillata) (L.f.) Royle). Aquatic Botany 12: 157-172.

So I think that neither the use of rich soils/substrates or water column ferts alone will provide the optimum conditions for plant growth. The optimum conditions can only be achieved by a combination of both methods. Of course you also noted this and so does Tom. Just found interesting the above paper.

cheers,

GM

 

[plantbrain]

Re: Introduction to Underwater Gardening with Soil Substrate

that roots are the "preferred" mechanism of nutrient uptake in aquatic plants is not necessary true as is demonstrated by this study:

Rattray MR, Howard-Williams C, Brown JMA (1991) Sediment and water resources of nitrogen and phosphorus for submersed rooted aquatic macrophytes. Aquatic Botany 40: 225-237

under oligotrophic conditions, a rich sediment positively affected plant growth. However, under eutrophic conditions, there was no difference in plant growth in sediment-rich and sediment-poor substrates. Plants took all the nutrients they needed from the water column.

cheers,

GM

This is also supported by Cedergreen and Madsen 2001 also in Aquatic Botany. They cut the roots off to make certain the stems could not get any sediment uptake.

Still, in both these studies, they ONLY considered a few limited weedy species...........they did NOT test for all 400 or so aquatic aquarium plants we grow. So while we might generalize and show examples.........we really do not have enough information to state this for ALL species.

So rather than taking that approach....which will not happen realistically..........we can hedge our bets and provide BOTH locations. This way, regardless of the plant and it's preferences, we have options avail for the plants and it makes any method that much more robust using both locations vs either-or.
This makes the most sense from a pragmatic and an aquarist's perspective.

 

[Tim Harrison]

Re: Introduction to Underwater Gardening with Soil Substrate

that roots are the "preferred" mechanism of nutrient uptake in aquatic plants is not necessary true as is demonstrated by this study:

Yep I totally agree, and thanks for the references all of which I am familiar with. I had more than a sneaking suspicion that I would be picked up on this, but serves me right, it was after all a bit of a sweeping generalisation and I should have taken the time to qualify it; which I have now done.

Research shows that given relative concentrations in the water column many aquatic plant species will preferentially uptake most of their nutrients from the substrate, particularly phosphorus, iron and other trace elements...But you are right too, research also shows many aquatic plant species will generally uptake some nutrients from the water column including, ammonium, potassium, calcium, magnesium, chloride, and sulfates.

I am sure that there are some plants that couldn't give monkey's either way, so...I suppose the salient question is - all else being equal - is the preferred location of nutrient uptake a significant determining factor with regards to limiting the growth of various species?

Regardless, as Tom mentioned, the research is still specific to relatively few of the 400 or so aquatic species familiar to hobbyists and therefore, as you both assert, it perhaps makes sense to adopt a pragmatic - belt and braces - approach within the context of our aquariums and use both locations; which after all is good horticultural practice.

Nevertheless, that said I know from experience there are many aquatic plant species that will grow vigorously and thrive in just soil alone (and whatever nutrients my tap water and fish food have to offer), and for years without showing any signs of nutrient deficiency. So, I guess it's also about choosing the right species to suit our unique aquarium conditions - and/or intended level of energy input - in the first place; which is also good horticultural practice.

 

[gmartins]

Re: Introduction to Underwater Gardening with Soil Substrate

I agree that these studies only focus on a limited number of species and that there are lot more out there. But then again, such is life. If at least one species shows a response different than the expected, we now know that observations cannot be generalised to all species. This happens a lot in science. There is just no way one can test ecological hypotheses on all species (for good sake). That's where meta-analyses can be handy to assess general patterns.

I agree that there are many examples of healthy plants being grown with rich soils but very little in the way of water-column ferts (just those in tap water and fish). Moreover, most species used are not true aquatics as they tend to live emersed during the dry season, where nutrients must be uptaken moslty via roots. So this makes us perceive that roots are really important and are the primary structure for nutrient uptake.
But then again, there are many examples (including myself) of plants being grown in bare inert substrates such as sand just with water-column ferts. and this includes species that are generally perveived as heavy root-feeders (Echinodorus, Crypts,....).

I'm not a plant expert (I'm a rocky reef ecologist working most with marine invertebrates and sometimes algae) but my thoughts are that higher plants are well adapted to take advantage of the situation. They are plastic in their responses to cope with environmental variation. This again suggests that optimum conditions are necessarily those including both methods (substrate and water), but neither alone is limiting of plant growth.

Let's give plants all the pobbibilities and let them pick what best suits their needs!!!

And yes I agree that for some, they couldn't care less. These are usually the most well adapted and with broad geographical distributions amongst which are the most successful invasive species. That's why they are so difficult to erradicate after established.

GM

 

[Tim Harrison]

Re: Introduction to Underwater Gardening with Soil Substrate

Thanks Tom an GM for your recent contributions, I have enjoyed reading your comments, and the lively discussion enormously.

 

[Tim Harrison]

Soil mineralisation/selfcycling mutually inclusive processes

I have recently updated the tutorial and made some additions, not least the section on water column dosing, but also a section on the use of garden soil, and I have added brief explanations why it is important not to layer the soil too deep and why the depth of the sand cap and grain size are important.

Many thanks to all those that have contributed in some way or another, through comments (challenging or otherwise) or constructive critism, or just questions that made me think a little deeper, both on this thread and those related to it. The tutorial is a work in progress and I am learning all the time and without that contribution I doubt it would be worth the effort.

In that vein I have also added the information below, which is an altered version of a response I made to another thread; I thought it might prove useful to set it in to the context of the tutorial so that all the relevant information can be found in one place. As the subject title suggests its mainly to do with Soil mineralization and tank cycling.

Soil/sediment metamorphosis
Newly submerged terrestrial soil goes through a number of chemical and biological changes before it becomes stable aquatic sediment. During these changes organic matter is broken down to form inorganic molecules, or the nutrients that plants can use; this process is often referred to as mineralization.

Mineralization of a submerged soil usually releases ammonia and other chemical compounds in to the water column where they can reach levels that are toxic to fish and invertebrates; but rarely to plants so it is usually safe to plant immediately. The use of macrophytes as water purifiers is well documented, so apart from adding instant interest, planting heavily from the outset will help to reduce ammonia and other chemical compounds to non-toxic levels. The plants will also often benefit from the additional nutrient load and CO2 given off during mineralization.

Self-cycling method
I have always found that the ammonia given off during mineralisation is more than adequate to cycle a filter so now is the time to hook one up. This self-cycling phenomenon is in effect fishless cycling but without the hassle of dosing ammonia, or adding fish food and suffering the subsequent consequences of phosphate build up. There is also far less water testing involved. I also add water conditioner that contains beneficial bacteria in the hope that it will speed the process up.

Rate of mineralisation
Mineralisation can take up to 2 months to complete, but the actual rate is determined by a number of factors such as the organic content of the soil, water and soil chemistry, and microbial activity. Planting heavily from the outset also helps to reduce the length of time it takes for newly submerged soil to stop giving off ammonia since macrophytes release O2 and organic compounds through their roots which will greatly increase microbial activity, and therefore nitrification and denitrification, in the forming sediment. The existing bacteria on plant roots will also help seed the sediment and perhaps further speed the process on its way.

Soil equilibrium
Eventually an equilibrium is reached and the soil substrate will actually start to absorb ammonia/ammonium from the water column where it will undergo nitrification. When levels of ammonia, nitrite, and nitrate stabilize within acceptable levels it’s a sign that denitrification is also well under way. If Nitrate levels are still a little high a substantial water change is usually all that is required to make the tank habitable to fish etc; this is where the sensible use of a decent test kit comes in to its own.

Mutually inclusive processes
Overall levels of ammonia, nitrite, and nitrate always seem to stabilize within acceptable levels quite quickly, often within a few weeks, which is borne out by the experience of others. So although it can take up to 2 months before mineralisation is complete - and therefore for the soil to stabilise as "aquatic sediment" - it is not usually necessary to wait anywhere near that long before adding fish etc. In this respect it probably helps to think of mineralisation and tank cycling as two separate but mutually inclusive processes.

Adding fish and invertebrates
Gradually add your aquarium critters one or two at a time over the space of a month or so to ensure that the system is not overwhelmed by the increasing bioload. The nitrifying/denitrifying qualities of the soil combined with the water purifying ability of macrophytes will probably prevent ammonia and nitrite reaching toxic levels, even with a partially cycled filter, but there’s no harm in exercising caution. It’s also a good idea to observe your critters closely during the settling in period for signs of stress.

 

[plantbrain]

Re: Soil mineralisation/selfcycling mutually inclusive proce

I have recently updated the tutorial and made some additions, not least the section on water column dosing, but also a section on the use of garden soil, and I have added brief explanations why it is important not to layer the soil too deep and why the depth of the sand cap and grain size are important.

Many thanks to all those that have contributed in some way or another, through comments (challenging or otherwise) or constructive critism, or just questions that made me think a little deeper, both on this thread and those related to it. The tutorial is a work in progress and I am learning all the time and without that contribution I doubt it would be worth the effort.

In that vein I have also added the information below, which is an altered version of a response I made to another thread; I thought it might prove useful to set it in to the context of the tutorial so that all the relevant information can be found in one place. As the subject title suggests its mainly to do with Soil mineralization and tank cycling.

As is often the case for the best result, group efforts and feedback really help. EI, list of levels and dosing, Non cO2, Excel usage, light/CO2 etc, all where group efforts and continue to be so.

Soil has long been overlooked, I do not use the rice paddy sediment we have even though it's pretty much identical to ADA AS, but this is due to aesthetics, not content or cost cutting. So if those are issues, then usign soil will help a lot for most any and every tank, whether it be high tech full blasting light, cO2, or no CO2/lower light and less input.

In both cases it adds something significant and positive. Thus I would offer as general advice, to all: use soil or ADA AS or the like in each case unless there's just not way around certain aesthetics.

 

[benleeph]

Re: Introduction to Underwater Gardening with Soil Substrate

Hi Tom,

Between paddy soil and MTS, which will be your preference in terms of rich sediment?

I have access to lots of paddy clay loam, any preparation needed?

 

[Stickleback]

Re: Zen and an Introduction to the Art of Underwater Gardeni

Back soon

AAAAAAAHHHHHHH

I need it! Please repost soon. This article is great, and I am just about to use the technique for a new tank.

Many thanks for putting it together.

S

 

[Stickleback]

Re: Zen and an Introduction to the Art of Underwater Gardeni

Bump


I'm setting up my tank tomorrow. i could really do with the great info that was in this article.

Please repost it.

S

 

[Tim Harrison]

Re: Zen and an Introduction to the Art of Underwater Gardeni

Bump


I'm setting up my tank tomorrow. i could really do with the great info that was in this article.

Please repost it.

S

Hi sorry, Practical Fish Keeping have published it as a two part series. The first part was in the newly released August edition and the second part will be in Septembers copy.

If you can't get hold of the mag and want any specific info let me know and I will do my best to help. A lot of it is in my journals anyway, such as they are, and in what remains of Zen.

viewtopic.php?f=49&t=18527&start=70
viewtopic.php?f=35&t=19761

 

[Stickleback]

Re: Zen and an Introduction to the Art of Underwater Gardeni

Congrats on the article, that's great news and well deserved. Would love to see more people going the low energy route.

Those journals are a great source of info, not as concise as the Zen article, but interesting to see it all thrashed out.

S

 

[gramski]

Great thread thanks to all the contributers.

 

[Delta_Raven]

great article and comments, thanks again ukaps posters!

 

[Tim Harrison]

Thanks, that's much appreciated. It's nice to know that the article is still proving useful.

 

[oldbloke]

Great article, many thanks.

 

[plantnoob]

an excellent , informative and not to mention inspirational read . selling up my co2 gear and going for it !

 

[d_scherrer]

Great article. Very informative. I have an issue that I hoping I can get some help with. I have a 75 gal panted aquairium and I need to do a large scale clean, scrub, and redo. Long vacation = algae issue. Anyway. This setup was my first attempt at a planted tank. I didn't do many things that should have been done with the substrate but I was still able to grow good looking plants. Now that I have my feet wet I want to re-setup using correct soil methods.
I have a substrate heater now, I am thinking this would be good to incorporate in this setup under the soil layer, thoughts?
Led lighting worth the investment?
Finally, the big problem. I have 7 HUGE Angel fish and a gaggle of neons, loaches, and other algae eating helpers. I don't have another tank and I only have the capacity to store everyone and the plants for a day or two tops. I have everything I need for a high tech setup including CO2, filtration, and T8 lighting. I plan to scale back a bit but will most likely keep using the equipment. With the fluval 401 I have 4 trays to work with. Any thoughts on how to get this tank setup and running will be helpful. Thank you much in advance.

 

[Tim Harrison]

Thanks for the positive feedback. I don't have any experience of heating cables, or LED lighting beyond my own DIY effort here at the bottom of the page The Dark Side or What Lurks Beneath | Page 3 | UK Aquatic Plant Society. So I'll let someone more qualified answer those questions.

With regards "the big problem", I have often introduced fish in to a newly set up soil substrate tank without any issues, and it becomes less of a problem if you have a mature filter to help reduce the inevitable ammonia spike. But I hesitate to recommend anyone else try it for obvious reasons.

If you have any other specific questions with regards helping to get the tank set up, throw them out there and I'm sure we'll all do our best to help.

 

[d_scherrer]

What was used to raise the level of the tank bed? Need a lightweight solution. Is the mesh something special in regards to chemical composition?
Thanks much.